Excerpt from the original CRV manual by Paul H. Smith:

Stage II responses tend to come in groups or “clusters” of words–usually 3-4 words, though sometimes more pertaining to different aspects or gestalts of the site. If for example a body of water and an area of land are present at the site, a group of sensory Stage II words might be produced by the viewer relating to the land, then another group relating to the water.

This is particularly noticeable in sites whose ideograms produce two or more “A” and “B” components. Stage IIs will tend to cluster in respect to the “A” and “B” components to which they relate. Stage II responses cluster in another sense as well. Frequently, types of sensory responses will come together. For example two or three tastes, smells, colors, or textures may cluster together as the viewer objectifies his perceptions on the paper.